I noticed I had been getting some weird finishes and a bit of play when pushing/pulling on my spindle ~0.1mm.

Disassembling the machine, the cars on the x and y axis had less preload compared to the z axis and would slide down the rail when held vertically.

So I decided to pull some cars apart and measure the balls..

measuring approx 20 balls
z axis car - balls were 3.974mm maybe a couple 3.973mm
x axis car - 3.967mm-3.972mm (mostly closer to 3.970mm)
y axis car - 3.959mm-3.970mm (average 3.965mm)

I have attached some photos on inside one of the y axis bearings, there seems to be some wear. looking at an x axis block only one of the bearing rows inside the block has some wear all the others are very shiny. The balls in both the x and y seem to be dull compared to the z axis.

The bearings were purchased from AliExpress which claim they are genuine but for the price...

Has anyone seen this before?

I'm guessing this is cause by misalignment maybe some dirt/chips in it? Should I throw them in the bin?

Unfortunately I've been burned pretty bad by everything I've bought from AliExpress (ball screws off centre, replacement ball screws bent, BK/BF bearings failing, faulty spindle etc..) I guess you pay for what you get.

Ritzy

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